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1.
Anthropogenic activities create various contaminated leachate, which can migrate downward from the vadose zone to groundwater,
transferring contaminants, including some hazardous ones.
When these various sources of contamination influence the groundwater aquifer simultaneously, the effects of contamination
are enhanced.
The major concern of this study has been to determine whether the shape of a groundwater chlorograph might be the result of
such deterministic effects as accumulation of one or more particular processes of groundwater contamination, and how this
might relate to specific hydrological situations.
This study proposes a classification of groundwater contamination on the basis of properties of the main components of groundwater
quality graphs and the corresponding hydrogeological/environmental situation.
The study further suggests that contamination of groundwater in any hydrogeological situation (e.g. sea water) may be graphically
expressed.
A variety of chlorographs and nitrographs, representative of various groundwater aquifers sampled from a number of wells throughout
Israel attest to this.
The study thus indicates that groundwater quality graphs may be considered as a complementary tool for groundwater quality
control and better understanding aquifer situations. 相似文献
2.
Mohamed Chiban Amina Soudani Fouad Sinan Saida Tahrouch Michel Persin 《洁净——土壤、空气、水》2011,39(4):376-383
Low cost adsorbents were prepared from dried plants for the removal of heavy metals, nitrate, and phosphate ions from industrial wastewaters. The efficiency of these adsorbents was investigated using batch adsorption technique at room temperature. The dried plant particles were characterized by N2 at 77 K adsorption, scanning electron microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, and phytochemical screening. The adsorption experiments showed that the microparticles of the dried plants presented a good adsorption of heavy metals, phosphate, and nitrate ions from real wastewaters. This adsorption increased with increasing contact time. The equilibrium time was found to be 30 min for heavy metals and nitrate ions and 240 min for phosphate ions. After the adsorption process, the Pb(II) concentrations, as well as those of Cd(II), Cu(II), and Zn(II) were below the European drinking water norms concentrations. The percentage removal of heavy metals, nitrates, and phosphates from industrial wastewaters by dried plants was ～94% for Cd2+, ～92% for Cu2+, ～99% for Pb2+, ～97% for Zn2+, ～100% for ${\rm NO}_{{\rm 3}}^{{-} } $ and ～77% for ${\rm PO}_{{\rm 4}}^{3{-} } $ ions. It is proved that dried plants can be one alternative source for low cost absorbents to remove heavy metals, nitrate, and phosphate ions from municipal and industrial wastewaters. 相似文献
3.
Water containing nitrate levels above 45 mg/l is not recommended for human consumption and its prolonged intake is associated with various health conditions. In Merida city, Mexico, the only source for water supply is a karstic aquifer, but the absence of sewerage and drainage networks makes it highly vulnerable to anthropogenic contamination. In this work, the concentration and spatial distribution of nitrate in the Merida's karstic aquifer were assessed by statistical and geostatistical techniques. The sources of nitrate contamination were tracked by making statistical correlations between nitrate concentrations and key ions; the potential risk to human health was also estimated by using the Hazard Index (HI). A total of 177 groundwater samples were collected from the four water supply systems serving Merida, during 2012 and 2013. Nitrate concentrations from collected samples varied between 15.51 and 70.61 mg/l, with maximum and minimum concentrations per sampling point ranging from 47.47 to 70.61 mg/l and from 15.51 to 17.32 mg/l, respectively. Significant positive correlations (P < 0.05) between nitrates and chlorides, sulphates and potassium were found, which may indicate potential contamination from domestic wastewater and agricultural activities. The spatial distribution of nitrate concentrations in the aquifer revealed an increase in nitrates following a trajectory South–North West, towards central and northwestern zones within Merida Metropolitan Area. From the health risk analysis, it was found that infants exposed at current nitrate levels are at a higher risk (HIMAX = 1.40) than adults (HR < 1.0) and therefore, there is a clear need for implementing effective strategies to protect groundwater quality and to better manage and control nitrate pollution sources. 相似文献
4.
基于盐湖资源的硝酸熔盐储能材料性能研究 总被引：1，自引：1，他引：0
太阳能光热发电是可再生能源发展的主要方向。作为太阳能光热发电的核心技术,熔融盐以热容量大、粘度低、蒸汽压低、使用温度范围宽等诸多独特的性能优势,成为光热发电储能的首选。相比之下,硝酸熔盐具有优良的传热和流体流动等特性,使其在光热储热系统中的性能优势较为突出。我国盐湖地区具备太阳能光热发电的发展空间和优势,丰富的无机盐资源可以降低相关相变储能材料的生产成本,有利于推进太阳能的规模化发展、能源结构的调整优化。据此,立足于盐湖资源的开发利用,以硝酸盐系列传热蓄热介质的工业应用为背景,针对产业化的二元硝酸盐熔盐做了更深入的系统研究;在此基础上,通过添加硝酸镁,制备了低熔点的三元熔盐储能材料;并将碳纳米管引入到硝酸盐体系,进一步提升了其导热性能。这不仅为硝酸熔盐储热材料的制备提供了理论基础,也为其在光热发电的应用打开了更多的可能性。 相似文献
5.
A. Pulido-Bosch S. Bensi L. Molina A. Vallejos J. M. Calaforra P. Pulido-Leboeuf 《Environmental Geology》2000,39(7):791-799
Relatively high concentrations of NO3 usually have their origin in processes of organic pollution and excessive use of inorganic fertilizers. In the case of agricultural
areas, these activities may generate great quantities of nitrates. This fact has enabled us to use the nitrate ion to characterize
an exploited aquifer unit of a very complex aquifer system, as is the case for the Campo de Dalías aquifer system (SE Spain).
The shallow boreholes, which draw water from intensively cultivated superficial formations, yield waters with a high NO3 content. When the boreholes are deeper and penetrate low-permeability formations in the superficial layers, the waters contain
little NO3; similar to what happens in areas of recharge where agricultural activities are absent. In addition, using longitudinal sections,
it is possible to demonstrate the possible existence of connections between superficial and deep aquifers using NO3 as a tracer. Similarly one can locate those sectors responsible for contamination caused by the poorly lined boreholes themselves,
when they perforate more than one aquifer in a multiple aquifer formation.
Received: 22 December 1998 · Accepted: 20 March 1999 相似文献
6.
Water-borne infections are the most common causes of infectious diseases in developing countries, often resulting from the
lack of a protected water supply, a faulty water-supply system or improper sewage disposal. A recent study of 107 samples
from bore wells of Mysore city has revealed that 51 samples (47.66%) contain Nitrate greater than 45 ppm, an indication that
the water would be harmful for drinking. Out of 51 samples tested for faecal pollution, using a H2S-strip test, 37 samples turned black and these were subjected to microbial identification. Out of these 37 samples, 63 H2S producing strains were isolated and the H2S producing organisms are Klebsiella ozaene;Klebsiella pneumoniae;Proteus mirabilis;Proteus vulgaris;Salmonella sp. and Citrobacter freundi.
The frequency of occurrence of the above-mentioned six micro-organism strains are as follows: Proteus mirabilis (19);Proteus vulgaris (14);Citrobacter freundi (13);Salmonella sp. (8);Klebsiella pneumoniae (5); and Klebsiella ozaene (4). Klebsiella and Proteus are known to cause urinary infection and Salmonella intestional infection.
Received: 7 September 1998 · Accepted: 10 November 1998 相似文献
7.
A stepwise logistic regression (LR) model was generated to evaluate the association between contamination of groundwater by
nitrates with several risk factors such as soil types, farm facilities and practises, and well characteristics. The odds ratio
was calculated to estimate the degree of impact that the associated variables had on the risk of contamination in a semiconfined
multilayer aquifer underlying rural areas of Buenos Aires, Argentina. Duplicate farm groundwater samples (n = 160) were taken and nitrate was analyzed. Data, involving various farm factors, was gathered via two questionnaires concerning
farm’s general and productive aspects, and well characteristics. Statistical tests were run between nitrates and each variable
present in the survey. A 96.25% of the samples presented detectable nitrate levels, 40.91% of which had more than 45 ppm nitrates.
The final LR model involved five of the variables under study: well age, soil permeability, depth of water table, location,
and distance from well to contamination sources. Cross validation proved to be a good estimator of nitrate water contamination.
Suspicions about how these characteristics influence groundwater contamination by nitrates were confirmed, and as these five
factors represent a higher risk for this type of aquifer, their proper management may contribute to a better resource protection. 相似文献
8.
K. O. Uma 《Environmental Geology》1993,21(1-2):70-76
Measurements from over 40 dug wells completed within the shallow lateritic aquifer around the city of Sokoto showed nitrate enrichment ranging between 20 and 100 mg/l and mostly above the limits recommended for domestic use. The values generally do not show any depth control but were less for forested and residential areas and more beneath agricultural farmlands. Evidence from earlier measurements suggests that the input of nitrates occurred only in the last ten years and could be easily linked to land use practices. 相似文献
9.
Geochemical and hydrogeological research has been carried out on 109 wells in the alluvial plain of Florence, in order to evaluate conductivity and main chemistry of ground waters, the pattern of some possible pollutant chemical species (Fe, Mn, Cr, Cu, Pb, Zn, NO2, NO3), and the vulnerability of the aquifers. The plain is made up of Plio-Quaternary alluvial and lacustrine sediments for a maximum thickness of 600 m. Silts and clays, sometimes with lenses of sandy gravels, are dominant, while considerable deposits of sands, pebbles, and gravels occur along the course of the Arno river and its tributary streams, and represent the most important aquifer of the plain. The groundwaters analyzed belong to this aquifer or to the smaller ones, hosted in the gravel lenses. Most waters show conductivity values around 1000–1200 S, and almost all of them have an alkaline-earth-bicarbonate chemical character; these features are consistent with the mainly calcareous lithology of the aquifers. In the western areas a higher salt content of the groundwaters is evident, probably related to the presence of industrial activities which use water desalinators. Heavy metal and NO2, NO3 analyses point out that no important pollution phenomena affect the groundwaters; all the mean values of the chemical considered species are below the maximum admissible concentration (MAC) fixed by the European Community for drinkable waters. Nevertheless, some anomalies of NO2, NO3, Fe, Mn, and Zn are present in the plain. Apart from Mn, which seems to be released by certain calcareous gravels, the other anomalies have a local influence, since they disappear even in the nearest wells. The most plausible causes can be recognized in losses of the sewage system (NO2=3–4 mg/t); use of nitrate compounds in agriculture (NO3=60–70 mg/l); oxidation of well pipes (Fe 20 mg/l; Zn 6 mg/l). As regards Cr, Cu, and Pb, all the observations are below the MAC; therefore, the median values of < 3, 3.9, and 1.1 g/l, respectively, could be considered reference concentrations for groundwaters circulating in calcareous lithotypes, under undisturbed natural conditions. Finally, a map of vulnerability related to the most superficial and important aquifer has been elaborated on the basis of thickness and permeability of the covers. The map shows that the areas near the Arno river are highly vulnerable, for the minimum thickness (or lacking) of sediments covering the aquifer. On the other hand, in the case of pollution, several factors not considered in the map could significantly increase the self-purification capacity of the aquifer, such as the dilution of groundwaters caused by the feeding of the rivers, the bacteria oxidation of nitrogenous species, and the sorption capacity of clay minerals and organic matter with respect to trace metals. 相似文献
10.
Peter Bajto 《岩石学报》2004,20(4)
Dubravsky Massif菱镁矿体的开采产生了部分局限在石炭纪低裂缝渗透变质岩中的喀斯特型裂缝含水层。大量的开矿过程对含水层中的地下水循环和化学成分都造成了可观的变化。本文研究了在这种复杂条件下地下水化学成分变化成因模型。根据化学配位模型,计算出所选矿物的饱和指数,从而指示所有喀斯特裂缝含水层饱和带中的地下水对菱镁矿、白云石、方解石的过饱和度和石膏的不饱和度。假设地下水未受人类活动的污染,而白云石中黄铁矿的氧化对成矿影响甚微,则水化学数据的统计描述代表了含水层中的水文地球化学背景。矿山中矿石焙烧释放的富氮气体凝聚产生的醋酸,能促进菱镁矿和白云石的溶解。这样产生的地下水相对背景值来说则富集NO3,Mg,和TIC。因此,由于地下开矿,岩溶作用估计将是原来的1.5倍。尽管有污染,这些所测参数并没有超过斯洛伐克卫生保健部颁发的No.29／2002 Z.z.饮用水标准临界值。因此采矿后含水层的开采也是可行的。 相似文献